Striated Ground in the Venezuelan Andes

Abstract

Striated ground was found above 3 600 m elevation in the Páramo de La Culata, Pico Espejo and Pico Bolívar areas of the central Venezuelan Andes. This ground, formed by nocturnal freezing and diurnal thawing of the contained water, consisted of aligned lumps of fine to coarse sand, separated by small discontinuous channels (1–3 cm wide). Sorting was observed in the form of pebble-rich and pebble-poor zones. Striated ground in the process of formation showed that needle ice filled the channels before thawing. Lack of sorting is an indication of very recent formation, probably the previous night. The orientation of the striae is compared with the wind direction. This indicates that the formation of needle ice in the ground reflects the direction of the freezing wind, producing striae orientated in that direction, thus supporting Troll’s (1944) original observations.